does anyone know what the hell this is? to me it seems like some sort of crop nilating killer fungus. it does not appear to be light burn, but im not ruling that out either. its tough being stupid

it kicked in full blast during the most ripest part of these plants life (around half way flowering, going into 5 weeks),
my yield has now suffered the consequnces terribly
worst grow ever !!!!
needs prevention and a cure !!! any help thanks
